Adjusting means for control devices



NOVg 16, 1948. 1 J, RQTHWELL Zfl ADJUSTI'NG MEANS FOR CONTROL DEVICES Filed Aug. 27, 1946 2 Sheets-Sheet l New, ifi, 3948. J, 1. ffao'f-@WELL 2,453,861

DJUSTNG MEANS FOR- CONTROL DEVICES Filed Aug. 27, 1946 2 sheets-snaai 2 39 i @ff i; i

L/s gul/afan JoznlKaZ'utl 34, I *^2Q By: M i A' @byL/LmmA Patented Nov. 16V, 1948 Tao Pmizwl` forze-ica :ADJUSTING ltiv'ifn'Li-HVIC'S lApplicatimn August 27, 1946,*Sei1liivo. 65532299 'zfolims. (erin-21169) 'My preSIit invent-idd relates t0 `a`djtig`Mnlris for `(ont'rl 'devices "suoh as `autc intilcA `1`tric switches wherein it is 'desirable'` to adju'st'the vrange and di'fferentialof operation of the Switch. l

One-object of theA invention is tov prvideadifferential adjustingxeelanisin of's'iinple 0andine'xpensive construction' including a'spi'ing"`v`v'h1h'ls located Ainside the range spring.

Another objet is Lto provide 'an "adjustment means for the differential, which upon being'adjustedtioes not Vchange the rane'settirig.

Still another object is to'potidean'adjusting device for the range Spring, 'whih 'tirn'g'adjust- 'iner'it does not change'the 'adjustment-of tlie`dif 'vfe'rntial adjusting device.

`A further object 'is "to "pryide an Yadjlstin'g arrangement including a nutforadjustingthe 'range' spring, the nut being theade'd'on"'a"s`leeve Whieh in turn'isthreadedon a'statio'nary blt in suon manner tliat'turning `oftlie"s1e`eve cau-ses it to Vrn'ove longitudinally vthroughl tl'ie nut andv over the bolt'for'cli'angirig the setting'f' the diie'r'ental Spring.

A-With* these and thl'- objets 'in' Vi'WjIiiY Vntion consists in the Construction,arangnentand Combination f thefaTiSDts Aflltiy CYI adjustmet'me'chanism'Whreytlie"objectsntemplateld" are" attained; as'hjereiriaft'er'tmore fully set forth. 'pointed 'out' in' I'ny claims and illustrated in 'the 'accompanying drawing'sjwliein: l

'Fi'gurel is aplan viewof'a control'fswithwith the-cover vremoved, 'my adjusting means "being apniied' thereto. v

"Figure` 21S-a sectional viewlpartiallyontne line 2--2"of'1"i'gure 1 Showing"the control 'swithin closed position.

FgurefS isjan' end elevation of Figure `2loking 'at the left side of Figure `2 "arid with theicovr shown in'section.

Figure 4 is a-sectionalview slmilarto Fi'gre v'2 but-'slightly enlarged relative thereto' anfdfsliowing Athe controlv device irra diier'entpositi'on 'Withftlie 'differential widening -means in' operation,"and A Figure 5`is a'sectionalviewon the'linef-S 'f Figure l showinga vswitch' operatingfiaim.

-On the accompanying' drawings! haveiusedthe reference numeralfl''to indi'oate a base 'plate'nd Ii iafco'verltherefor. -Tnebase plate IU hasfan lupwardly `-embossed portion I2 "that *cooperates diaphragm chamber f-beneathflthe diaphragm f4 Within the range spring 32 I provide a differential spring 55 interposed between a shoulder 56 of the sleeve 28 and a flange 58 of a sleeve 51. The flange 58, when the parts are in the position of Fig, 2, is adapted to contact the upper end of the sleeve 24 and is guided by a sleeve 59 within the sleeve 24.

Practical operation As pressure under the diaphragm I4 increases, the right-hand end of the control arm I9 will rise. Somewhere between the lower limit of Fig. 2 and an upper limit beyond that shown in Fig. 4, the control arm I9 will pick up the flange 58 and lift the sleeve 51 away from the stop sleeve 24, thus adding the force of the differential spring 55 to that of the range spring 32. This will increase the differential of operation of the control device, depending upon the adjustment of the spring 55.

If the spring is omitted or its adjustment is zero, then of course the minimum differential is at the minimum inherent in the switch structure. The spring 55, as long as it is brought into operation before the upper limit of movement of the arm I9 is reached (where the toggle thimble 43 passes over center and opens the contact 4l and 42) will effect a widening of the inherent differential.

When it is desirable to change the differential of operation, a screw driver is associated with the slot 30 oi the sleeve 28 for rotating the sleeve, causing it to travel downwardly relative to the bolt 25 and likewise downwardly at the same rate relative to the nut 29, providing the internal and external screws of the sleeve have the same pitch. Thus we have adjustment of a differential spring located within a range spring without however changing the adjustment of the range spring itself during differential adjustments.

When it is desirable to change the adjustment of the range spring, the nut 29 is rotated, thus causing the nut to travel relative to the sleeve 28, which is in effect similar travel relative to the stationary bolt 25, thus effecting a change in compression of the range spring without in any Way changing the adjustment of the differential spring.

An arrangement of this character permits the differential spring to be located within a range spring instead of having to take up other space within the control housing. Range springs in control devices of the character disclosed are ordinarily relatively large and heavy and have plenty of room within them to receive a differenti'al spring in the manner disclosed. The arrangement of the bolt, sleeve and nut 25--28--29 is such that either adjustment can be effected without the adjustments interfering with each other.

Some changes may be made in the construction and arrangement of the parts of my adjusting means without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim as my invention:

1. In adjusting means for a control device having a control arm, a range spring, a stationary threaded element, a sleeve threaded thereon, a range adjusting nut for the range spring threaded on said sleeve, a differential springv within the range spring and engaging said sleeve for adjustment thereby when the sleeve is adjusted relative to said threaded element and said range adjustl tween said control arm and said nut, a differential spring wholly inside said range spring and cooperable with said control arm during its movement for widening the differential of operation of said control arm, and adjusting means for said differential spring threaded in said nut and extending into said range spring.

3. In adjusting means for a control device having a control arm, a range spring, a stationary threaded bolt, a sleeve threaded thereon, a range adjusting nut for the range spring and threaded on said sleeve, a differential spring within said range spring and engaging said sleeve for adjustment thereby, a stop sleeve on said bolt for said differential spring, said control arm during movement from one limit to another being effective to engage said differential spring and move it from said stop sleeve, the force of said differential spring being thereupon imposed on said control arm.

4. In combination with a control arm operable between opposite limits of movement, range and differential adjustment mechanism therefor comprising a range spring, and a differential spring within said range spring, a stationary element, a nut for adjusting said range spring, a sleeve for adjusting said differential spring, said sleeve being threaded in said nut and threaded on said stationary element whereby rotation of said nut relative to stationary element and said sleeve changes the adjustment of the range spring and rotation of the sleeve relative to said stationary element and said nut changes adjustment of the differential spring, said differential spring being picked up by said control arm at a point intermediate the limits of movement of the arm.

5. In a control structure, a control arm, pressure-operated means to move said arm between opposite limits, a control device moved to one position by said control arm at one of its limits and to another position at another limit of movement of the control arm, a stationary bolt passing through said control arm, a sleeve threaded thereon, a nut threaded on said sleeve, said nut and bolt having the same pitch whereby rotation of the sleeve relative thereto and relative to the bolt leaves the nut at the same distance from the control arm, a movable element on said bolt, a stationary stop therefor, a range spring interposed between said nut and said control arm, and a differential spring interposed between said sleeve and said movable element, said control arm being engageable with said element for moving it from said stop during a portion of the movement of the control arm from one of its limits to the other.

6. In a control structure, a control arm, pressure-operated means to move said arm between opposite limits, a control device moved to one position by said control arm at one of its limits and to .another position at another limit of movement of the control arm, a stationary bolt passing through said control arm, a sleeve threaded thereon, a nut threaded on said sleeve, a movable element'von said bolt, a stationary stop therefor, a

range spring interposed between said nut and said control arm, and a diierential spring interposed between said sleeve and said movable element.

'7. In a control structure, a control arm, range and differential springs therefor, pressure-operated means to move said arm between opposite limits, a stationary bolt, a. sleeve threaded thereon for adjusting said differential spring, a nut threaded on said sleeve for adjusting said range spring, the internal and external threads of said sleeve being of the same pitch to prevent movement of said nut toward or away from said control arm when adjusting said sleeve, a movable element on said bolt, and a stationary stop therefor, said control arm being engageable with said element for moving it from said stop during a portion of the movement of the control arm from one of its limits to the other.

JOHN J. ROTHWELL.

REFERENCES CTED The following references are of record in the le of this patent: 

